original late 1920's vintage american wall-mount commercial building elevator cab push button backplate designed and fabricated by or for the otis elevator company, new york city, ny. the rectangular-shaped bronze metal backplate contains a single opening once containing a black push button, and amber glass inset with the words "in use" lightly etched on the backside (visible when illuminated). the centrally located medallion containing the otis elevator medallion was lost long ago. nicely aged patina left untouched. measures 7 1/4 x 2 1/2 inches.